Residential hydronic heating systems often include water expansion tanks since thermal expansion of heated water may occur wherever water is heated in a closed system (e.g., when boiler water is isolated from the public water supply by a one-way valve, such as a feed water pressure reducing valve, backflow preventer, check valve, etc.). Water expansion tanks are designed to absorb the increased volume of water caused by thermal expansion and maintain a balanced pressure throughout the hot water heating system. The expansion tanks prevent system damage and unnecessary relief valve discharge caused by excessive pressure from thermal expansion.
Water expansion tanks, as well as other components of residential hydronic heating systems such as pressure reducing valves, require periodic maintenance. Accordingly, water expansion tanks are often separated from the system by an isolating ball valve so that the expansion tank can be isolated from the heating system for maintenance and repair, as well as a purge ball valve so that the expansion tank can be drained of water during the maintenance and repair.
What is still desired is a new and improved valve assembly that can be used, for example, to connect an expansion tank to a residential hydronic heating system.